This invention relates to cigarette packers in which the cigarette blocks to be packed are composed in the alveolar chamber of a forming hopper and from the said chamber are transferred to respective machine compressor drum pockets, after passing through a cigarette block compacting duct. For this block transfer, use is made of pushers, with pushing elements shaped in conformity with the alveolar chamber, and guided in such a manner as to be compelled to follow an operative path which comprises a straight transfer path section along which the alveolar chamber is aligned with one of the compressor drum pockets through the interposed compacting duct. A pusher device of this type is illustrated, for example, in the pending U.S. application No. 798 557 (ZULLO) filed May 19, 1977.
More particularly, the pusher of this invention belongs to those of the type in which many pushers are mounted equispaced between each other onto an endless conveyor, such as a belt, driven so as to continuously move in one direction. In known devices of this type, the use of cams is required or other equivalent means, possibly in association with springs, to move the pusher, during its return stroke, into a position of complete disengagement with respect to the compressor drum and to the compacting duct. Due to the high working rates of modern packers, the cam systems and the like involve high inertia forces, with all the consequent inconveniences and disadvantages.
The purpose of this invention is to realize a continuous pusher of the above type, particularly adapted for transferring in sequence cigarette blocks from the composition alveolar chamber of the block forming hopper, to the respective pockets of the associated block compressor drum, through the compacting duct of a cigarette packer machine.
Substantially, the device according to the invention consists of a complex driving assembly, with endless flexible means, such as a pair of toothed belts or flat link chains, equal to each other and guided in equal manner in interspaced and parallel vertical planes, with the belts driven at the same level, but horizontally staggered in the direction of their extension, while among these belts there is operatively mounted for each pushing element a corresponding telescopic support, to which there is associated the relative pusher which is thus subjected to a traversing motion in a closed circuit, according to a path having a straight run in line with the said composition alveolar chamber and with the port of the compacting duct of the block being transferred, while an initial section of the "exit" path of each belt of said pair, on the side towards the compressor drum, is so guided as to fall out-of-the-perpendicular in relation to the end of the overlying straight run of the belts; said device comprising also a third endless flexible drive, such as a belt, similar and similarly arranged in relation to those of the above mentioned pair to which it is operatively associated, but having a less marked out-of-the-perpendicular downward run, and located farther back; to this third drive there is articulately coupled the rod of the pushing element of each of the said traversing telescopic supports, in such a manner that, as soon as a pusher has completed its forward stroke which brings a cigarette block into the corresponding compressor drum pocket, the said third belt causes the correlative telescopic support to be oscillated backward, while it is about to begin its descent along the out-of-the-perpendicular runs of the belts which guide it, thus determining the immediate disengagement of the relative pusher from the already pushed block whereby this pusher, as soon as it has introduced the block into the pocket, it is immediately and positively withdrawn from the block head, so as to completely avoid any sliding contact of the pushing element with it.
These and other features of the invention and the resulting advantages will be understood from the following detailed description of a preferred embodiment, made with reference to the attached drawings.